Seat armrest



FIG. 1 is a perspective view of a seat armrest showing my new design;

FIG. 2 is a side elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is an end elevational view thereof viewed from the connection end; and,

FIG. 5 is an end elevational view thereof viewed from the free end.

The broken line showing of the seat is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a seat armrest, as shown and described. 